Today's radio communications systems are able to provide communication coverage to communication units located throughout a large geographical area. Generally, this is accomplished by a plurality of smaller coverage areas, or sites, whose site controllers are linked via a regional network, to provide continuous coverage across the combined coverage areas. In multi-site arrangements, such as the one described, it is typical for the coverage areas of adjacent sites to overlap. That is, a communication unit located within the overlapped area may be able to communicate with the site controllers from either of two, or more, coverage areas.
When a trunked communication call is initiated, the voice signals for the call must reach each of the communication units which are to receive the call. That is, the voice path must traverse through each of the site controllers currently being used by the target communication units. For example, if each of five communication units are using different site controllers, a communication among these five communication units would necessarily include the participation of each of the five site controllers. However, because of overlapping coverage areas and the location of the communication units within such coverage areas, the required number of site controllers is often less than the total number being used at the time the call is made. Referring again to the example, suppose that three of the five communication units are located in an overlap coverage area which can be serviced by the same site controller. Note that this scenario, which is not at all uncommon, actually requires the use of only three site controllers to complete the call (i.e., one each for two isolated units, and one for the three units in the overlap area). Unfortunately, today's trunked communication systems make no attempt to reduce the number of site controllers needed to establish a voice path.
Accordingly, a trunked communications system which provided the ability to determine a reduced number of site controllers necessary to complete a call would be an advantage over the prior art. Further, a method which could be employed to collapse trunked calls to a reduced number of sites would enhance the efficiency, and hence through put of the communication system.